Study of Numerical Processing Speed, Implicit and Explicit Memory, Active and Passive Memory, Conservation Abilities, and Visual-Spatial Skills of Students with Dyscalculia

Background and Purpose: Learning disorder is one of the common disorders in students, which can lead to the occurrence of educational problems and secondary disorders in them. Based on psychopathological criteria, dyscalculia is one of the subcategories of learning disorder. Children with this disorder have problems in perception of spatial relations and in different cognitive abilities. Therefore, the present research aimed to compare the cognitive-perceptual abilities like numerical processing, implicit and explicit memory, active and passive memory, conservation ability, and visual-spatial skills in children with dyscalculia and normal students.     Method: This study was of causal- comparative design. The sample consisted of 70 students with learning disorder selected by convenience sampling from centers for learning disability in Karaj and Qazvin and 80 normal students selected by multistage random sampling. The used instruments included Wechsler Intelligence Scale (WIS), Visual- Spatial Memory Test (Cornoldi, 1995), Active - Passive Memory Test (Cornoldi, 1995), Explicit and Implicit Memory Test (Snodgrass and Vanderwart, 1980), Iran Key Math Diagnostic Test (Cornoli et al., 1976), Numerosity Processing Speed Test (Cappelletti et al., 2007), and Conservation of Liquid Task with Bogardo and Russ method (1991). Data were analyzed by multivariate analysis of variance. Results: The findings demonstrated that there were significant differences between the groups in terms of liquid conservation, explicit memory, active memory, numerical processing speed, and visual-spatial skills (p <0.001). However, no significant difference was observed between the groups in the components of passive and implicit memory (p <0.05). Conclusion: Based on the obtained results, it can be concluded that the children with dyscalculia have more problems in conservation ability, visual-spatial ability, and numerical processing speed. These deficits are not related to the intelligence but to the executive functions, especially the active memory. Therefore, it can be suggested that these components are among the distinctive characteristics of this group of students with special learning disability and should be paid special attention at the time of identification and planning for treatment.